It used to be the case that only movies that performed well at the box office were lined up for sequel/prequel treatment, a Hollywood trait which had the useful side-effect of saving audiences (so far) from such prospective horrors as The Big Lebowski II, Harold and Maude II and Eraserhead: The Early Years. Then late last year along came Tron Legacy, a follow-up to the much-loved lo-fi 1980s cult classic with oodles of shiny CGI but very little of its predecessor's 8-bit charm.

Unfortunately, the film did pretty well at the box office. Can it be a coincidence that just a few months later, Deadline is reporting that film company Alcon has secured the rights to make prequels, sequels, spin-offs and pretty much everything else they can think of (bar a straight remake) to Blade Runner, Ridley Scott's dark and dystopian tale of replicant-ridden Los Angeles? We seem to have entered a new era in which cult movies that never looked like potential franchise material are resurrected and revamped decades later whether those who treasure them really want it or not.

Of course, prequels and sequels are not in themselves terrible things. Few (bar those who sneer at Tolkien's writings as the preserve of cardigan-sporting, real ale-drinking fellows with lots of facial hair and a penchant for Clannad's back catalogue) are complaining that Peter Jackson is about to embark on his long-awaited two-film adaptation of The Hobbit, for instance. The difference is that while that project is a bonafide adaption of the 1937 children's novel which preceded Lord of the Rings, Philip K Dick wrote no sequel to Do Androids Dream of Electric Sheep?, the science fiction novel upon which Blade Runner was based. Any movie follow-up therefore has legitimacy issues right from the beginning.

KW Jeter, a friend of Dick, did in fact write three follow-up novels which attempted to resolve some of the differences between Blade Runner and its source novel. I haven't read them, but perhaps somebody out there has? The fact that the first tome, Blade Runner II: The Edge of Human, didn't arrive until 1995, a full 27 years after Do Androids Dream of Electric Sheep? was first published, rather fills the nose with the pungent whiff of hackery. And yet there was some talk of turning that book into a film a few years back.

"What does it mean to be human?" wrote Wright. "That's the central question in life and the paramount question in science fiction. More pointedly: is or isn't Deckard a replicant? What happens to Rachel? What are the off world colonies like? What happens to replicants once Tyrell is killed by one of his creations? These are some of the questions we explored with [producer] Bud Yorkin for a few years and I believe are a great basis for a story many fans like me are dying to see."

One way Alcon might get fans of the original film onside would be to hire Scott himself to work on a follow-up. The veteran director once seemed disinclined to enter sci-fi sequel territory, but his forthcoming movie Prometheus – billed as a film set "in the same universe" as his classic 1979 slasher-in-space flick Alien – suggests this may no longer be the case. I'm not predicting a masterpiece should the British director actually get the call (after all, we haven't yet seen the fruits of his labour on Prometheus) but it might be a decent starting point.

What is not always mentioned in articles about Blade Runner is that the original book is a very different beast from the film. Like a lot of 1950s and 1960s sci-fi it reads rather whimsically to a modern audience with its emphasis on a society where animals are rare and electronic pets are a coveted, preposterously expensive prize. It was Scott and his screenwriters Hampton Fancher and David Peoples who saw the potential to transform Dick's basic story into a form of science-fiction noir. All the right elements: the rich man, the femme fatale and the investigating agent, were already in place, but were not played up in the book. Even if his output has not always been consistently brilliant in the decades since, it is Scott who best deserves the chance to take it forward. If there has to be a sequel, please let it be a Ridley sequel. Better still, let's hope the whole project ends up getting lost in time (as Roy Batty would say) like tears in rain.